Composite bicycle frame with integral electrical interconnections and method of manufacturing same

ABSTRACT

A composite bicycle frame which comprises of a main frame including interconnected tubes and substantially composed of a composite material and having a composite layup structure. At least one electric wire electrically interconnects electrical components mounted to or in the frame. The at least one electric wire is embedded in the composite material structure forming the composite main frame. The electric wire has connectable conductive ends at each of the opposed ends thereof.

TECHNICAL FIELD

The application relates generally to bicycles having composite framesand to methods of manufacturing such bicycles and composite bicycleframes.

BACKGROUND

In most known bicycle frames, regardless of their material, a majorityof the length of each of the shifter cables runs along the outside ofthe bicycle frame tubing, although it is also known to pass these cablesinside the bicycle frame tubing.

A bicycle frame 1 of the prior art, which may be formed of a metal or ofa composite material for example, is shown in FIG. 1 and includesshifter and brake cables which at least partially run along the outsideof the bicycle frame tubing. The bicycle frame 1 comprises a main frame2. The main frame 2 includes a seat tube 3, a top tube 4, a down tube 5,a head tube 6, seat stays 7, chain stays 8 and a bottom bracket 9. Theseat tube 3 is connected to a first end of the top tube 4. The head tube6 is connected to a second end of the top tube 4. The bottom bracket 9is connected to the bottom end of the seat tube 3. The down tube 5 isconnected to the head tube 6 and the bottom bracket 9. The seat stays 7are connected to the seat tube 3. The chain stays 8 are connected to theseat stays 7 and the bottom bracket 9. In the bicycle frame 1, theshifter cable 10 runs along the down tube 5 to the bottom bracket 9. Thebrake cables 11 run along the top tube 2.

The shifter and brake cables of the bicycle frame 1 may also at leastpartially run inside the hollow interior of the tubes forming thebicycle frame, and may for example be fed down through the hollow insidecavity defined within the down and/or top tubes 5 and 4 for example.While this generally improves the overall look of the bicycle, as anyunsightly cables are substantially hidden from view because they are fedthrough the hollow tubes, these tubes must necessarily be hollow andfurther the assembly step required in feeding the cables through theframe is add time and cost to the overall bicycle assembly process.While bicycles have for years used mechanical gear shifting systemswhich require cables having moving inner cables within a stationaryouter sheath which is fixed at both ends to the frame, recentdevelopments have led to electronic gear-shifting systems becoming morewidely available, including for example the Di2™ system made byShimano™. In such electronic gear-shifting systems, riders are able toshift gears using electronic switches instead of convention gear controllevers. Such switches are connected by an electric wire to a batterypack and to a small electric motor which drives the derailleur, used todisplace the bicycle chain from one gear cog to the next. However,although such electronic gear-shifting systems have become morecommonplace, the configuration and method used to feed the electricwires interconnecting the various components of the electronicgear-shifting system has remained substantially the same.

SUMMARY

It is therefore an object to provide an improved composite bicycle framewhich is particularly adapted for use with electronic components, suchas but not limited to, electronic gear-shifting systems and/orelectronic braking systems.

In accordance with one aspect of the present invention, there isprovided a composite bicycle frame comprising: a main frame includinginterconnected tubes, the main frame being substantially composed of acomposite material and having a composite layup structure; and at leastone electric wire adapted for electrically interconnecting electricalcomponents mounted to or in the frame, the at least one electric wirebeing embedded in the composite material structure forming the compositemain frame, the electric wire having opposed connectable conductiveends.

In accordance with another aspect of the present invention, there isprovided a bicycle comprising: an electrical system mounted to thebicycle, the electrical system comprising at least a first electricalelement and a second electrical element; and a frame includinginterconnected tubes, the frame being substantially composed of acomposite material and having a composite layup structure, the framehaving at least one signal-carrying cable embedded in the compositelayup structure thereof such as to be integrally formed within thecomposite material of frame, the signal-carrying cable interconnectingthe first and second electrical elements of the electrical system.

There is also provided, in accordance with a further aspect of thepresent invention, a method for manufacturing a composite bicycle framehaving a composite layup structure, the composite bicycle framecomprising a main frame including interconnected tubes, the methodcomprising the steps of: partially forming the main frame with layers ofcomposite fibre and/or molding compound; providing the partially formedmain frame with at least an electric wire laid within the layers of thecomposite fibre and/or molding compound, the electric wire havingconnectable conductive ends; completing the main frame with the electricwire embedded within the composite layup structure of the compositebicycle frame and the connectable conductive ends are exposed; andcuring the main frame of composite fibre layers and/or molding compoundin a mold to form the composite bicycle frame with the electric wireembedded within the composite layup structure.

Further details of these and other aspects of the present invention willbe apparent from the detailed description and figures included below.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying figures, in which:

FIG. 1 is a perspective view of a bicycle frame having shifter and brakecables running along the bicycle frame tubing in accordance with theprior art;

FIG. 2 is a perspective view of a bicycle frame in accordance with thepresent disclosure having at least one electric cable embedded in thecomposite layup structure of the bicycle frame tubing;

FIG. 3 is a partial section view of the bicycle frame tubing of FIG. 2,with the electric cable embedded between layers of composite material;and

FIG. 4 is a block diagram of a method for manufacturing the bicycleframe of FIG. 2 in accordance with the present disclosure.

DETAILED DESCRIPTION

Referring now to the drawings and more particularly to FIG. 2, thebicycle 20 of the present disclosure includes a bicycle frame 30 atleast a majority of which is composed of a composite material, andtherefore which has a composite structure. The term “compositestructure” or “composite layup structure” as used herein is understoodto refer to any suitable composite (i.e. non-metallic) material whichmay be used for the purposes of a bicycle frame. The composite materialas defined herein includes fibres within a resin matrix. However, in atleast one possible embodiment, the composite material may be constructedusing an assembly of fibre prepreg cloths of varying modulus and tow,which are assembled and bonded within a resin matrix to form a compositelayup structure after a high temperature curing and/or molding step. Thecomposite frame 30 may therefore be composite material such as carbonfibre. In one embodiment the frame 30 of the bicycle 20 is entirelycomposed of the composite material, however the frame 30 may alternatelycomprise only a portion of which is made of a composite material.

Although the bicycle 20 will generally be described herein withparticular reference to the frame 30 thereof, it is to be understoodthat the bicycle 20 includes all other components which are typicallyincluded on a bicycle, such as the front an rear wheels, a saddle andseat post mounted to the seat tube, a front fork mounted to the headtube, as well as handle bars, etc connected with the front fork.Although gears, the chain, pedal cranks, etc. are not depicted in FIG. 2for simplicity, it is to be understood that such components also formpart of the bicycle 20 as described herein. Additionally, the presentlydescribed bicycle 20 may be a road bicycle, a mountain bicycle, or anyother hybrid type variety thereof (ex: “cross” or city bike, etc.).Although the bicycle 20 as shown in FIG. 2 is depicted as a rigid or“hard tail” bicycle (i.e. it does not have any rear suspension system)such as which may be used on the road, it is to be understood that theframe 30 of the present bicycle 20 may also be employed on a mountainbicycle having a rear suspension system and thus which may not have atraditional rear triangle configuration nor a rigid rear structure.

Regardless of the type of bicycle, therefore, the bicycle frame 30includes generally a main frame 31 having at least a seat tube 32, a toptube 34, a down tube 36, a head tube 38, and a bottom bracket 44. Theframe 30 may also include seat stays 40 and chain stays 42, however asnoted above depending on the configuration of the particular bicyclethese may from part of a separate part of the bicycle frame, such as forexample a rear swing arm assembly. In the embodiment depicted in FIG. 2,the seat tube 32 is connected to a first end of a top tube 34, and thehead tube 38 is connected to a second opposed end of the top tube 34.The bottom bracket 44 is connected to the bottom end of the seat tube32. The down tube 36 is connected to the head tube 38 and the bottombracket 44. In the bicycle depicted in FIG. 2, which is a “hard tail”bicycle (i.e. it does not have any rear suspension system), the seatstays 40 are connected to the seat tube 32, and the chain stays 42 areconnected to the seat stays 40 and the bottom bracket 44.

The bicycle 20 is equipped with one or more electronic derailleurs, suchas the front derailleur 41 shown graphically in FIG. 2 and located nearthe bottom end of the seat tube 32 adjacent the bottom bracket 44.Accordingly, the bicycle is equipped with corresponding electronicshifters (not shown) which may be located on the handlebar 39 mounted tothe stem which extends through the head tube 38 of the frame.

The frame 30 of the bicycle 20 comprises at least one (i.e. one or morethan one) electric wire 46 embedded within the composite material whichforms at least a portion of the frame 30. In one embodiment, at leastone electric wire 46 is embedded in the composite layup structure of oneor more of the tubes forming the main frame 31, such as the down tube 36for example. Accordingly, as will be seen in more detail below, at leasta majority of the overall length of the electric wire 46 is thereforeintegrally formed within the composite material of one or more tubes ofthe frame 30 during the manufacturing process of the composite materialitself, such as to be permanently embedded within the compositematerial. The electric wire 46 includes terminal connectors 60 at eachof its opposed ends, and in at least one embodiment these terminalconnects 60 are also integrally formed and embedded within the compositematerial forming the frame 30. For example, a first one 62 of theterminal connectors 60 may extends from the head tube 38 for connectingwith the shifters, and a second one 64 of the terminal connectors 60extends from the seat tube 32 or the down tube 36 adjacent the bottombracket 44 for connecting with the front derailleur. As in thisembodiment the terminal connectors 60 are also integrally formed with,and thus embedded within, the composite material of the frame 30, inorder to connect the electronic components of the electronicgear-shifting system mounted to the bicycle 20 one needs only to plugthe electronic shifters and the electronic derailleurs into theirassociated terminal connectors 60 formed directly into the frame 30.

In at least another embodiment, however, the terminal connectors 60 areexterior to the composite material forming the frame 30, i.e. notintegrally formed and not embedded within the composite material formingthe frame 30. Accordingly, the remote end of the electric wire 46 havingthe first one 62 of the terminal connectors 60 thereon may extend fromthe head tube 38, and the opposed remote end of the electric wire 46having the second one 64 of the terminal connectors 60 may extend fromthe seat tube 32 or the down tube 36 adjacent the bottom bracket 44. Thefirst one 62 and the second one 64 of the terminal connectors 60 performthe same function as described above, but are simply not themselvesintegrally formed within the composite material of the frame 30.

It is also contemplated that the embedded conductors may have aninsulating sheath at their ends which extend out of the tubes whereinthe wire inside the shielded cover may be exposed by stripping an end ofits insulating sheath for connection with the different modules.

The term “embedded” when used herein is understood to refer to theelectric wire being substantially entirely enclosed within, or made anintegral part of, the composite material structure of the bicycle frame30, as shown in more detail in FIG. 3. As such, at least a majority ofthe electric wire is embedded and electrically shielded in the compositematerial itself, rather than being simply bonded or otherwise fastenedto an outer surface thereof. It is to be understood, however, that thevery remote ends of the wire may however extend beyond the compositeframe, and thus may protrude therefrom at each end of the wire. The wireso embedded is still considered to be substantially entirely embeddedwithin the composite material of the frame in as defined herein.

Referring now to FIG. 3, a portion of a tube 43 of the composite frame30 is depicted with several composite layers having been striped awaysuch as to shown the electric wire 46 embedded between layers ofcomposite fibre, in accordance with the composite frame 30 of thepresent bicycle 20. In this embodiment, the electric cable 46 is thusembedded between layers of “pre-preg” of the composite material formingthe frame 30, and may for example be disposed within the composite layupstructure between the fourth layer 45 and the fifth layer 47 as shown inFIG. 4, however of course any combination may be possible provided theelectric wire 46 is in fact embedded within the composite materialitself during the manufacturing process of the composite material priorto the final molding or curing process. The wire 46 may be shielded orhave an electrically insulating sheath. Additionally, as noted above thecomposite material forming the bicycle frame 30 may not in fact includepre-preg layers, however the electric cable(s) 46 are neverthelessembedded within the composite fibre and resin matrix material whichforms the composite material, and in fact the electric cable(s) 46 areintroduced therein during the production of the composite frame prior tothe final molding process step. It is also pointed out that the cablecould also be embedded in other suitable moulding compound in acompression molding process.

The embedding of one or more electric wires 46 in the composite layupstructure of the composite frame 30 means that the electric wires orcables which may be used for the electronic shifting systems and/orelectronic braking systems are integrally formed within the compositeframe 30 itself during the manufacturing process.

Referring back to FIG. 2, in one embodiment the electronic shiftingsystem 37 of the present bicycle 20 may include a front derailleur 41and a rear derailleur 35 which are controlled by, and electricallyinterconnected with, electronic shifters 33 mounted to the handlebars 39via the one or more electric cables 46 which are embedded within thecomposite material of the frame 30. The electric cables 46 may thereforeeach extend between one or more electronic shifters 33 to one or morederailleurs 41, 35. In the depicted embodiment, the front derailleur 41is located near the bottom end of the seat tube 32 adjacent the bottombracket 44, and the rear derailleur is located near the rear end of thechain stays 42 adjacent the connection with the seat stays 40.

In one particular embodiment, the frame 30 may also comprise additionalelectric wires or cables 70 embedded in the composite layup structure ofthe composite frame 30. For example, an electric cable 70 may be used tointerconnect the front and rear derailleurs 41, 35, wherein only asingle electric cable 46 may run within the frame 30 from the electronicshifters 33 to the front derailleur 41, and then the additional electriccable 70 may run within the frame 30 from the front derailleur 41 to therear derailleur 35. As per the electric wire 46 described above, theelectric wire 70 includes terminal connectors 72 on opposed endsthereof, which are also integrally formed, and thus embedded, within thecomposite material of the frame 30. A first one 74 of the terminalconnectors 72 extends from the end of the chain stray 42 for connectingwith the rear derailleur 35, and a second one 76 of the terminalconnectors 72 extends from the chain stays 42 adjacent the bottombracket 44 for connecting with the front derailleur 41.

As also illustrated in FIG. 2, in at least one possible embodiment thecomposite frame 30 may also comprise electric brake cables/wires 90 thatare similarly embedded within the composite layup structure of the frame30, for use in conjunction with an electronic braking system for thebicycle 20. For example, a first brake cable 92 which includes a first94 and second 96 end may be integrally formed within the top tube 34,for example, and may include first 94 end of the first brake cable 92disposed near the head tube 38 for connecting with a rear wheel brakeactuator, and a second end 96 of the brake cable 92 disposed near theseat stays 40 and/or the seat tube 32 for connecting with an electronicrear wheel brake calliper. A second brake cable 98 may also beintegrally formed within the composite frame 30 and may include first100 and second 102 ends. The first end 100 of the second brake cable 98is located for example near the head tube 38 for connecting with a frontwheel brake actuator, and the second end 102 of the second brake cable98 may be located near the head tube 38 for connecting with the frontwheel brake calliper.

Although the electric cables/wires have been described for use inconjunction with an electronic shifting system (comprising electronicderailleur(s) and shifter(s) for example) and/or with an electronicbraking system (comprising electronically actuated brakes for example),the electric cables/wires 46, 70 described herein as being embeddedwithin the composite layup structure of the composite frame 30 may alsobe used for other signal and/or current carrying purposes. As such, theelectric wires/cables described herein may be used to electricallyinterconnect components of an electrical system mounted to the bicycle,wherein the electrical system may comprise for example a first actuatingelement (such as the electronic shift lever) and a second actuatedelement (such as the electronic derailleur(s)). Additionally, theelectric wires 46, 70 embedded within the composite material of theframe 30 as described herein may also be used to feed power to orreceive signals from other components on the bicycle 20, such as but notlimited to, electronic speed and/or distance indicators/calculatorsmounted to the handle-bar, electrically controlled shocks, lights,digital screen and/or interfaces, etc. Additionally, in at least anotherembodiment, the embedded electric wires 46, 70 may be connected tosensors also embedded within the composite frame 30, and therefore maybe used for transmitting monitoring information about the compositematerial itself, such as for example to determine and warn of thepresence of cracks, or to measure pressure and/or temperature of thematerial or of the surrounding environment. In a further embodiment, theelectric cables/wires embedded within the composite layup structure ofthe frame 30 may also be used in for the purposes of electronic and/orelectrical applications, such as for example a LCD screen. Such a LCDscreen may, for example, be integrated directly into the composite frame30. The LCD screen may also be a flexible screen that is itself directlyintegrated into the composite material of the frame. However, it is tobe understood that most standard LCD screens could only be introducedinto the composite frame after the frame has been molded due to the hightemperatures involved. However, if the LCD screen is capable ofwithstanding the high temperatures required during the compositematerial molding and curing process, that it could also be integrateddirectly into the composite material before the molding step during theproduction thereof.

In all cases, however, the electric wires/cables 46, 70 described hereinmay be used for the transmission of a power signal and/or of a datasignal, and therefore may be used either to provide current to anelectrical device (either mounted on or embedded into the frame) or totransmit and/or receive data to and/or from the electrical device towhich it is in electrical communication.

In at least one further possible embodiment, the wires/cables 46, 70embedded within the composite frame 30 may also comprise optical fibrecables/wires that may be used for the same purposes as described above,albeit that they transmit a data signal via light transmitted throughthe fibre optic cable.

Referring now to FIG. 4, a block diagram of a method 80 formanufacturing the composite bicycle frame 20 of FIG. 2 in accordancewith the present disclosure is illustrated. In the method 80, a bicycleframe 30 having a composite layup structure is manufactured. Thecomposite bicycle frame 30 of the bicycle 20 is as described above.

In step 82 of the manufacturing method 80, at least the main frame 31 ofthe composite frame 30 is partially formed with layers of prepreg inaccordance with methods known in the art of forming composite layupstructure. The term “prepreg” is understood to refer to fibres in aresin matrix. These usually take the form of a weave or areuni-directional or a chopped fibre mat. They already contain an amountof a resin or matrix material used to bond them together and to othercomponents during manufacture. The term “matrix material” when usedherein is understood to refer for example to resins which are commonlyused in the manufacture of composite bicycle frames. The term “compositefibres” when used herein is understood to refer, for example, tonon-metallic fibres which are embedded within a resin, and which is anon-metallic material used for bicycle frames. Such composite materials,such as but not limited to those made with carbon fibres for example,are light-weight, corrosion-resistant and strong, and can be formed intoalmost any shape desired. Other materials besides carbon fibre, such asmetallic boron, can be added to the matrix to enhance stiffness further.Kevlar fibres may also be introduced into the carbon weaves to improvevibration damping and impact strength. Other molding compounds may beused in a compression molding process of the frame and may not containprepeg composite fibres.

In step 84, the frame 30 of prepreg layers is provided with at least oneelectric wire 46, the electric wire 46 having terminal connectors 60disposed at each of the opposed ends of the wire. The electric wire 46may include an insulated outer sheath which is compatible with themanufacturing condition of the bicycle frame 20, i.e. the prepreg layersand the curing conditions.

In step 86, the frame 30 of prepreg layers is completed to the desiredsize with layers of prepreg such that the electric wire 46 issubstantially fully embedded in the prepreg layup and the terminalconnectors 60 are also integrally formed within the layers of prepreg.The electric terminals of the connectors 60 remain exposed, but theterminal connections 60 of each of the electric wires 46 remain embeddedand insulated within the composite material of the frame 30.

In step 88, the main frame 30 of prepreg layers is placed into a moldand is cured, in accordance with the methods known in the art of formingcomposite layup structure, to form the composite frame 30 of the bicycle20 having one or more electric wires 46 embedded within the compositelayup structure of the frame.

The above description is meant to be exemplary only, and one skilled inthe art will recognize that changes may be made to the embodimentsdescribed without departing from the scope of the invention disclosed.The term “embedded” as used herein, with reference to the electriccables/wires which are disposed directly within the composite material,is understood to mean that the said wires are encapsulated andelectrically insulated by the composite material itself during themanufacturing process of the composite material, for example prior tothe final molding or curing process thereof. The electrical cables/wiresmay also be shielded or have an outer electrically insulated sheath. Assuch, regardless of the number of layers of fibre prepreg which aredisposed overtop of the integrated electrical wires, if any at all, thewires are said to be imbedded in that they are integrally andmonolithically formed within the material during its production, and arenot merely adhered to an outer or inner surface of an already formedmaterial. However, this does not exclude that the presently describedembedded wires cannot be integrally formed with the composite materialon the very outer or inner surface of the composite tubes of the presentbicycle. The bicycle frame 30 has been generally described herein asbeing composite, which may mean that in at least one embodiment it iscomposed of a carbon fibre formed within a resin for example. However,other composite materials may of course also be used to form thepresently described bicycle frame 30. The electric wires 46, 70described herein are understood to be current or electric signalcarrying wires/cables which interconnect electronic and/or electricalcomponents such as to conduct an electric signal or power from onecomponent to another (i.e. such as to connect these components inelectrical communication). These wires/cables 46, 70 are understood tobe different and distinct from traditional cables which physically slidewithin surrounding sheaths in order to physically connect traditionalshift levers and derailleurs, or traditional brake levers and brakecallipers. Still other modifications which fall within the scope of thepresent invention will be apparent to those skilled in the art, in lightof a review of this disclosure, and such modifications are intended tofall within the appended claims.

What is claimed is:
 1. A composite bicycle frame comprising: a mainframe including interconnected tubes, the main frame being substantiallycomposed of a composite material and having a composite layup structure;and at least one electric wire adapted for electrically interconnectingelectrical components mounted to or in the frame, the at least oneelectric wire being integral with the composite material forming thecomposite main frame and fixed in place therein, the electric wirecomprising connectable conductive ends having terminal connectors ateach of opposed ends of the electric wire, the terminal connectors ofsaid electric wires being integrally formed within the composite layupstructure of the composite main frame, and external wire end portionsecure to said terminal connectors being electrically insulated.
 2. Thecomposite bicycle frame of claim 1, wherein the electrical componentsinclude at least one of an electronic shifting system and an electricbraking system.
 3. The composite bicycle frame of claim 2, wherein saidinterconnected tubes comprise at least a seat tube, a top tube, a headtube, a down tube and wherein a bottom bracket is secured to some ofsaid tubes.
 4. The composite bicycle frame of claim 3, wherein a firstone of the terminal connectors is disposed proximate the head tube forconnecting with electronic shifters of the electronic shifting system,and a second one of the terminal connectors being disposed proximate theseat tube or the down tube for connecting with one or more derailleursof the electronic shifting system.
 5. The composite bicycle frame ofclaim 1, wherein the composite layup structure comprises carbon fibre.6. A composite bicycle frame comprising: a main frame includinginterconnected tubes, the main frame being substantially composed of acomposite material and having a composite layup structure, the mainframe further having at least one electric brake cable integral with thecomposite layup structure of the frame; and at least one electric wireadapted for electrically interconnecting electrical components mountedto or in the frame, the at least one electric wire being integral withthe composite material forming the composite main frame and fixed inplace therein, the electric wire comprising connectable conductive endshaving terminal connectors at each of opposed ends of the electric wire,the terminal connectors being exterior from the composite layupstructure of the composite main frame, an external wire end portionsecured to said terminal connectors being electrically insulated.
 7. Thecomposite bicycle frame as claimed in claim 6, wherein saidinterconnected tubes comprise at least a seat tube, a top tube, a headtube, a down tube and wherein a bottom bracket is secured to some ofsaid tubes.
 8. The composite bicycle frame as defined in claim 6,further comprising an electronic shifting system.
 9. The compositebicycle frame as defined in claim 8, wherein the electronic shiftingsystem comprises a first actuating element and a second actuatingelement, the first actuating element includes at least one electronicshifting actuator and the second actuating element includes at least oneelectronic derailleur.
 10. The composite bicycle frame as defined inclaim 6, wherein the terminal connectors are integrally formed withinthe composite layup structure of the composite material of said frame.11. The composite bicycle frame as defined in claim 6, wherein the mainframe has at least one signal-carrying cable configured to carry a powersignal and/or a data signal between first and second electricalelements.
 12. The composite bicycle frame as defined in claim 11,wherein the signal-carrying cable is an electric wire.
 13. The compositebicycle frame as defined in claim 11, wherein the signal-carrying cableis an optical fibre cable.
 14. The composite bicycle frame as defined inclaim 6, further comprising an electronic braking system.